Retractable ball caster



July 9, 1963 N. A. RABELOS 3,096,536

RETRACTABLE BALL CASTER Filed March 31, 1961 INVENTOR.

NICHOLAS 4- 2485406 vwm United States Patent 3,096,536 RETRACTABLE BALL CASTER Nicholas Arthur Rabelos, Atlanta, Ga., assignor to Roll-Lok Corporation, Atlanta, Ga. Filed Mar. 31, 1961, Ser. No. 99,843 1 Claim. (Cl. 16-26) This invention relates to retractable ball casters and more particularly to casters adapted for application to the supporting surface of various objects which require movement to and from different locations and it consists in the constructions, arrangements and combinations herein described and claimed.

Quite often chairs equipped with ordinary casters have been used as a substitute for a ladder, which casters are constantly contacting a floor surface. Under such practice, the person will be required to stand upon the seat and in an attempt, for instance, to reach a high elevation, the person may be required to lean in such a direction as to impart movement to the casters, resulting in his or her unbalance and consequent fall from the chair with possible serious injuries. Additionally, ordinary casters will mar a supporting surface when moved thereacross.

It is therefore the cardinal object of the invention to provide a construction of ball casters for various objects wherein the ball of the casters are retractable automatically into an inoperative position upon application of pressure upon the rollers and thereby cause the object to firmly seat upon a floor or other surface; the roller being automatically movable to operative position upon removal of weight or pressure upon the object supported by the rollers.

More specifically, it is an important object of the invention to provide a roller type caster which is constructed of few parts, readily assembled and which may be installed in supporting means, such as table and chair legs, without the use of special tools and by the average person having limited mechanical ability.

It is a still further object of the invention to provide a caster construction wherein the main supporting roller which is automatically projectible and retractable, is provided with additional bearing members enhancing the rolling action of the supporting roller.

Additional objects, advantages and features of invention will be apparent from the following description, considered in conjunction with the accompanying drawing, wherein,

FIGURE 1 is a perspective view of a chair having the ball casters installed in the lower portions of the legs thereof.

FIGURE 2 is a fragmentary longitudinal section taken on the line Z-2 of FIGURE 1.

FIGURE 3 is a cross section taken on the line 3-3 of FIGURE 2.

FIGURE 4 is a fragmentary vertical section through a slightly inclined chair leg, illustrating the relative position between the ball caster and the leg.

FIGURE 5 is an exploded perspective view of the parts constituting the caster, and

FIGURE 6 is a vertical section of a supporting member of an article of furniture or the like, illustrating a modification of the caster.

In the present instance, I have preferred to disclose the caster as being installed upon a chair, generally indicated by the reference character 10, which as usual comprises supporting legs 11, which in the present instance, are shown as formed of hollow metallic tubing. However, it should be understood that the present caster is not limited to such construction of a leg, since obvious-ly the caster may be readily installed in other types 3,096,536 Patented July 9, 1963 of legs, by merely removing the old type caster and substituting the present caster therefor.

Attention is now invited to FIGURES 2, 3, and 4 wherein it will be seen that the caster generally indicated at 12 comprises a sleeve 13 of such dimensions as to be frictionally mounted within the opening 14 of the leg of the chair, and as shown comprises a plurality of circumferentially spaced, longitudinally extending ribs 15 adapted to contact the interior surface of the opening 14 for firmly securing the caster within the leg. These ribs 15, in addition to securing the sleeve within the opening 14, also provide passage of any air which may be trapped in the opening of the leg, upon initial installation of the caster sleeve.

The lower end of the sleeve 13 is formed with an annular flange 16' of a diameter slightly greater than the terminal end of the leg, for a purpose presently to be explained.

The sleeve 13 has a conical bore 17 forming a seat for a roller member 18 suitably mounted within a retainer housing 19, which as best seen in FIGURE 5 comprises an encircling band 20, which at its lower end is of .a diameter slightly less than the upper end thereof, so as to retain the spherical ball member and prevent passage thereof. Integrally formed with the band 20 there are a plurality of fingers 21 of such curvature as to freely overlie the ball member 18 to permit free rotation thereof, as well as to house the ball.

The fingers 21 in addition to retaining the ball member in operative position within the cylinder, also form a seat for a helical spring 22 which is disposed within the cylinder 13 and interposed between the fingers and a plastic disk 23 retained in the open end of the cylinder by means of an inwardly extended flange 24. The disk 23 is of a resilient character enabling it to be presented into the cylinder and snap beneath the flange 24 for retaining the parts in assembled relation.

In the modified form shown in FIGURE 6, the parts corresponding to the construction described are indicated by primed reference characters.

The retainer housing 25 of the modified form, is pro vided at the upper or inner end thereof with an annular raceway 26 within which a plurality of small ball bearings 26 are confined by means of an inwardly extended flange 28, which bearings are in rolling engagement with the roller member 18'.

From the foregoing description of the caster, it will be seen that when the chair is unoccupied, the roller member 18 or 18' will be in the projected position as shown, which will enable the chair to be moved freely and noiselessly upon a supporting surface without liability of marring the surface. By virtue of the fact that the terminal end of each leg 11 or 11' rests directly upon the flange '16 or 16' of the respective sleeve 13 and 13, the roller member and retainer housing will move in unison into projected or retracted position of the roller member 18 or 18'. Thus, when weight of a person or pressure is applied to the seat of the chair, the leg 11 or 11 and the sleeve 13 or 13' will move downwardly, causing the roller member 18 or 18' and retaining housing to move upwardly into the leg thus compressing the spring 22 or 22' due to contacting engagement with disk 23 or 23'.

When the person arises from the seat or pressure on the chair is removed, the spring 22 or 22 will project the In a caster device for articles of furniture and the like,

a sleeve adapted to be frictionally engaged within an opening of the leg of an article of furniture, said sleeve having a plurality of circumferentially spaced longitudinally extending ribs for engaging the wall of the article of furniture, the lower end of said sleeve having an annular flange of a diameter slightly greater than the opening of said leg for contacting engagement therewith, the lower end of said sleeve having an arcuate seat, a ball retainer housing mounted in said sleeve, said retainer housing comprising an encircling band in said seat for embracing a roller member, said encircling band at the lower end thereof being of a diameter slightly less than the upper end thereof for retaining the roller member therewithin, the lower end of said band being arranged below the lower end of said sleeve, said retainer housing having a plurality of integral fingers of such curvature as to freely overlie the roller member within the retainer housing, all of said fingers being of the same size and shape, and said fingers extending inwardly from the upper end of said band and said fingers having their upper ends terminating in pointed end portions which are spaced slightly from each other, the upper pointed end portions of the fingers being closer to each other than are the lower end portions of the fingers which are integrally joined to the band, the inner end of said sleeve having an inwardly turned flange, said last named flange having a 25 Circular formation, a closure member of yieldable material within the sleeve and said closure member comprising a disk of resilient construction enabling it to be presented into the sleeve and snapped beneath the last named flange for retaining the parts in assembled position, a helical spring interposed between said closure member and said retainer housing, said fingers in addition to retaining the ball member in operative position also form a seat for said helical spring, the upper ends of said fingers being positioned at a slightly higher elevation than the lower end portion of the helical spring, said roller member normally projecting beyond the annular flange on the lower end of said sleeve and said roller member being movable to a position inwardly of said last named flange upon a downward pressure on the caster device against the resilient resistance of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 229,478 Schoen June 29, 1880 642,921 Reed Feb. 6, 1900 1,301,139 Laskowski Apr. 22, 1919 2,590,052 Stuits Mar. 18, 1952 2,973,546 Roch Mar. 7, 1961 FOREIGN PATENTS 18,968 Great Britain Aug. 29, 1902 177,751 Canada May-Aug. 1917 

